Pumping assembly

ABSTRACT

The present invention relates to a pumping assembly that has a first pump and a second pump connected to an end cap, which the connection is in a back-to-back configuration in some arrangements. The end cap, which can be centrally located, has a core that is in liquid communication with a first and second port on the end cap by way of a conduit. The conduit combines the flow of the first pump and the second pump at the core, which then exits the assembly by way of at least one of the ports.

BACKGROUND OF THE INVENTION

This invention is directed toward a pumping assembly. More specifically, and without limitation, this invention relates to a hydrostatic pumping assembly with a two pump assembly having only two ports.

Pumping assemblies are well known in the art. One problem with current pumping assemblies relates to providing larger displacements. Larger displacement requires increasing the size of components and elements related to force considerations, such as shafts, bearings, and rotating kits. The increase in size, and the associated costs, limits the ability to design larger displacement pumping assemblies. Likewise, those pumping assemblies that do have larger displacements are difficult to manufacture and distribute due to the cost of production and retail cost for such pumping assemblies.

The use of larger displacement pump assemblies are also slower compared to smaller pump assemblies because of the large components present in the larger displacement pump assemblies. So although a greater displacement is reached, the pump is not as fast.

This in turn has led to end-consumers attempting to combine the plumbing of two smaller displacement pumping assemblies to provide a larger displacement, which can be less expensive than a larger displacement pumping assembly. However, this approach also has its deficiencies. The combination of two pumping assemblies in this manner causes unnecessary duplication of elements that provide for additional points of failure and inhibits proper flow of the combined pumping assembly thereby decreasing efficiency. These redundancies also increase costs along with the costs related to additional hoses and fittings used to plumb the pumps together. Additional plumbing also extends the length of the system.

When two pumps are used to provide a greater displacement, the pumps are controlled independently and function as separate or individual pumps irrespective of the presence of the other pump. This further complicates operation of such a pumping assembly.

Thus it is a primary objective of this invention to provide a pumping assembly that improves upon the art.

Another objective of this invention is to provide a pumping assembly that allows the incorporation of existing qualified components.

Yet another objective of this invention is to provide a pumping assembly with a larger displacement.

Another objective of this invention is to provide a pumping assembly with two pumps and simplified plumbing.

Yet another objective of this invention is to provide a pumping assembly that reduces redundant elements.

These and other objectives, features, and advantages of the invention will become apparent from the specification and claims.

SUMMARY OF THE INVENTION

In general, the present invention relates to a pump assembly. The pump assembly includes a first pump and a second pump that are connected to an end cap that has only a first port and a second port. This arrangement allows the use of pumps that have been previously designed and qualified to be combined to provide a larger displacement substantially the same as their combined displacement. The use of smaller pumps to achieve a larger displacement rather than a single larger pump having the same displacement allows for superior performance associated with smaller parts. Similarly, the ability to use existing pumps reduces time and costs dedicated to design and development.

Sharing the first port and the second port shortens the related plumbing while eliminating components that are needed when separate pumps are used. Similarly, the shared ports allows for the pump to operate in tandem, which improves performance.

In some arrangements of the present invention, the pumps are variable displacement pumps. The use of variable displacement pumps provide a range of displacements, including those available from each individual pump and the combination of pumps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-away side view of a pumping assembly;

FIG. 2 is a side view of a pumping assembly; and

FIG. 3 is a schematic view of a pumping assembly.

DETAILED DESCRIPTION

With reference to the Figures a pumping assembly 10 is shown having a first pump 12 and a second pump 14 connected to an end cap 16. The first pump 12 and the second pump 14 are hydrostatic variable displacement pumps that are configured to operate independently of each other or in combination. For example, the first pump 12 is a 210 cc/rev pump and the second pump 14 is a 210 cc/rev pump, which provide a combined 420 cc/rev.

The end cap 16 has a first side 18 and a second side 20 with a core 22 therebetween that is shared by the first pump 12 and the second pump 14. In the arrangement shown, the end cap 16 is centrally located with the first pump 12 and the second pump 14 connected in an end-to-end fashion such that the first pump 12 and the second pump 14 substantially mirror each other.

A conduit 24 is in liquid communication with the first pump 12 and the second pump 14 is in liquid communication with the core 22. In this way the flow from the first pump 12 and the second pump 14 flows from the respective pump 12, 14 to the core 22. The core 22 is in liquid communication with a first port 26 and a second port 28 that extend through to the core 22 from a third side 30 of the end cap 16. In other arrangements, the first port 26 is on the third side 30 and the second port 28 is on a fourth side 32 of the end cap 16. The first port 26 and the second port 28 are the only ports on the pumping assembly 10, which are both in communication with the first pump 12 and the second pump 14.

In the exemplary embodiment shown in the Figures, the first pump 12, second pump 14, and the end cap 16 share a housing 34 providing a one-piece pump assembly 10. In other arrangements, the first pump 12 and second pump 14 have their own independent housing that connects to the end cap 16, which provides a three-piece pump assembly 10.

In some embodiments, the first pump 12 and second pump 14 each have a control system 36, a bearing 38, a shaft 40, a rotating kit 42, a valve plate 44, a swashplate 46, a servo 48, and one or more valves 50. In other embodiments, some or all of these elements are shared. As seen in the Figures, the pump assembly 10 has a shared shaft 40.

In operation, the first pump 12 and the second pump 14 receive a flow from the first port 26 that is pumped in tandem by the first pump 12 and the second pump 14 through the conduit 24 and into the core 22. From the core 22 a combined flow that has a cc/rev that is substantially equal to the combined cc/rev of the first pump 12 and the second pump passes out the second port 28. When the control system 36 is shared, the first pump 12 and second pump 14 are controlled together. In other arrangements, the first pump 12 and the second pump 14 are capable of separate control, including when the first pump 12 and the second pump 14 have variable displacement, which allows for a greater range in selective displacement.

Therefore, a pumping assembly 10 has been provided that allows the incorporation of existing qualified components, has a larger combined displacement than the pumps, simplifies plumbing, reduces redundant elements, and improves upon the art.

From the above discussion and accompanying figures and claims, it will be appreciated that the pumping assembly 10 offers many advantages over the prior art. It will be appreciated further by those skilled in the art that other various modifications could be made to the device without parting from the spirit and scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby. It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in the light thereof will be suggested to persons skilled in the art and are to be included in the spirit and purview of this application. 

What is claimed is:
 1. A pumping assembly, comprising: a first pump and a second pump connected to an end cap; and a first port and a second port that extend through the end cap and are in communication with the first pump and the second pump; wherein the pumping assembly has only the first port and the second port.
 2. The pumping assembly of claim 1 wherein the first pump and the second pump are assembled back-to-back.
 3. The pumping assembly of claim 1 wherein the first pump and the second pump are variable displacement pumps that are configured to operate separately and in combination.
 4. The pumping assembly of claim 1 wherein the first pump and the second pump are positioned on opposite sides of the end cap.
 5. The pumping assembly of claim 1 wherein the first port and the second port share a common core.
 6. The pumping assembly of claim 1 wherein the first pump, the end cap, and the second pump are within a shared housing.
 7. The pumping assembly of claim 1 wherein the first pump and the second pump are configured to operate in tandem to provide a combined flow that passes from the first pump and the second pump and through at least one of the first port and the second port.
 8. A pumping assembly, comprising: a first pump and a second pump connected to an end cap; and a first port and a second port that extend through the end cap and are in communication with the first pump and the second pump; wherein the first pump and the second pump are configured to operate in tandem to provide a combined flow that passes from the first pump and the second pump and through at least one of the first port and the second port.
 9. The pumping assembly of claim 8 wherein the first pump and the second pump are assembled back-to-back.
 10. The pumping assembly of claim 8 wherein the first pump and the second pump are positioned on opposite sides of the end cap.
 11. The pumping assembly of claim 8 wherein the first port and the second port share a common core.
 12. The pumping assembly of claim 8 wherein the first pump, the end cap, and the second pump are within a shared housing. 